Caster



A. K. NIXON.

EASTER- APPLICATION FILED JULY 27.1921.

PatentedSept. 12, 19220 I 121M822 tor A ll) ion KNizon fliiorn egrPatented Sept. 12, 1922.

- UNITED STATES 1,428,899 PATENT orrlcs.

ALBION K. NIXON, OF SAN FRANCISCO, CAL]:IEQIRNJLL, ASSIGNOR O'FONEFH'IALF TO ALBERT GASFER, 0F VALLEJO, CALIFORNIA.

(FASTER Application filed July 27, 1921. Serial No. 487,935.

To all whom it may concern:

Be it known. that I, A BI K. NIXQN, a citizen of the United States,residing in the city and county of San Francisco and State ofCalifornia, have invented new and useful Improvements in Casters, ofwhich the following is a specification 'This invention relates to acaster, and especially to a caster of the compound roller type.

One of the objects of the present invention is to generally improve andsimplify casters such as are used in conjunction with heavy furniture,pianos or the like, and especially to. provide a caster in which rollingfriction is greatly reduced, 1narring of the floor surface, etc},prevented, and in which jarring of the article supported and resistanceto override an obstruction when encountered is reduced to a minimum.

Further objects will hereinafter appear. The invention consists of the,parts and the construction, combination and arrangement of parts ashereinafter more fully de scribed and claimed, having reference to theaccompanying drawings, in which Fig.1 is. a side elevation of one formof the caster,

Fig. 2 is a cross section of the same. Fig. 3 is a perspective view ofthe roller guard.

Fig. 4 is. a side elevation of another form of thecaster.

I Fig. 5 is a cross section of the same.

i Referrin to the drawings in detail, and particularly to Fig. l, Aindicates the shank of a caster, 2 the upper head, 3 the lower head, and4 the bearing arms of the caster. The heads 2 and 3 are secured withrelation to each other in the usual manner as indicated at 5, and a ballbearing race 6 is interposed between the head members to permit a freeswivel action between the same. The arms 4: of the caster are interposedas shown in Fig. 2, and connecting the lower ends of the arms is abearing pin 7, upon which is journaled a roller 8. This roller isdisposed within a second roller generally indicated at 9 which willhereinafter be termed the track rmg. This ring is formed of shee me orany suitable material, and is considerably largerin diameter than theroller 8. Formed. on the inner side of the ring is an annular rib orridge l0, and formed in the center p on f the roller 81s a gr v ll,which permits the roller 8 to straddle the rib 10,

thus permitting the rib to form a track for the'roller 8, which securessaid roller against lateral movement with relation to the track member.

By referring to Figs. 1 and 2, it will be seen that the diameter of theroller 8 is so small when comparison is made with the interior diameterof the track member 9, that unless means were provided for main-.taining the roller 8 in constant engagement with the inner side of thetrack member. displacement of the ring or roller 8 might take place. Toavoid such displacement, a guard generally indicated at 12, has beenprovided. This guard consists of a pair of arms 14:, the lower ends ofwhich are per.- forated as at 15 to permit the pin 7 to passtherethrough. The upper ends of the arms 14 are connected by across-piece 16, and this piece is bent or grooved as at 17 to straddiethe rib or track 10. The guardthus formed maintains the roller inconstant engagement with the inner surface of the track member and therib 10, and thus prevents displacement of the roller with relation tothe track member or vice versa.

In the other form of the invention illustrated in Figs. 4 and 5, a trackring 18 is employed. The inner surface of the 'ring is concaved as at.19 to form a track for aroller 20. The exterior surface. of this rolleris convex to conform with the inner formation of the track ring. Thecaster in general, illustrated in Figs. 4 and 5, is also provided with apair of connected swivel heads 21 and 22 and the bearing lugs shown at23 support the bearing pin 24:, upon which the roller 20 is journaled.

For the purpose of securing the roller against lateral movement, andalso for the purpose of maintaining it in engagement with the innertrack surface 19, a pair of side plates 25 and 26 have been provided.These side plates enter annular recesses 27 and 28 formed in therespective sides of the track ring, and they. are freely turnable inthese recessesandi they are also freely turnable upon the pin 24. i

To prevent unnecessary friction between the track ring and the sideplates 25 and 26, and between theend surfaces of the roller 20, the pin24: is shouldered as at 30. This shouldering of the pin maintains apredetermined spacing between the roller 20 and the the same function asthe guard 12 and the annular rib or track member 10. 7

There are three main objects sought in the present invention: First, tominimize rolling friction; second, to prevent marrin of I surfacesrolled over or upon, and thir to I 65 iat41, the track ring remainsstationary and prevent jarring of the article supported and resistanceto override an obstruction when encountered.

The first object is obtained by-providing the compound rollers indicatedat 8 and 9. The rolling friction takes place between the I outer surfaceof the smallroller and the in ner surface of the trackring. The innersurface of said track ring, where depressions would have a tendencytoexist, is composed of material of a harder substance than the planeswhich sustain the outer'ring when in motion. The depressions which wouldbe caused on the'surface of the material: rolled upon, when a load isapplied to the roller, will be minimized. The inner surface of the trackring being curved gives more of a bearing surface to the small rollerthan would be given if the roller came in direct contact with a planesurface, such as a'wooden floor, thereby decreasing depression andminimizing friction.

The second object is obtained by applying soft rubber, or other suitablematerial, to the outer portion of the track ring as indicated at 40.This surface comes in contact with the hard wood floor when in motion;the rubber forming a' cushion between the roller, the track ring and thefloor. Actual rolling wear and tear take place on the insidesurface ofthe track ring, that is the ring acts as a track only when the roller isin motion.- The soft rubber on the outer surface of the track ring givesa large bearing support when a load isvapplied, and it does not hinderthe rolling effect of the track ring.

T e third object is obtained by employing the track ring. When itapproaches: an obstruction, for instance, such as indicated forms aninclined track for the roller 8 between thepoints indicated at 42 and43. The roller 8 rolls within the track ring while this remainsstationary, that'is the roller 8 moves from the point 43 to the point 42and when it passes the high pointof the obstruction, which is indicatedat 42, it is obvious that the :track'ring will'follow and that the trackring'and the roller will become centered with relation to each etherwhen a plane} or even surface" is again reached. I i a This action ofthe two rollers one with relation to the other is important as it notonly lessens the jar to the article supported, but it materially reducesthe amount of power or force required to override an obstruction.

While certain features of the present invention are more or lessspecifically illustrated, I wish it' understood that various changes inform and proportion may be resorted to within the scope of the appendedclaims, similarly that the materials and finish of the several partsemployed may be, such as the experience and judgment .of themanufacturer may dictate or varying. uses yd ma d- Having thus describedmy invention, what I claim and desire to secure by Letters Pat ent is g'1. In a device of the character described, a compound roller supportcomprising a circulartrack member, and a roller adapted to travel on theinner surface of the tr'ack mem-. ber'gone'of said members having agroove therein and the other of said'me'mbers being formed to operate insaid groove. 7

2. In a device of the character described, a compound roller supportcomprising a circular track member, and a roller adapted to travel onthe inner surface of the track member, one of said members having'agroove therein and the other of -said meme bers being formed 'to operatein said groove, and a guard device arranged between. the track memberand the roller members to maintain said members in cooperative relation.

3. A device of the character described comprisin a swivel head, a pairof bearing arms carried by the head, a bearingpin disposed between thearms, a roller journaled thereon, a track ring exterior of theirollerthereon, a track ring exterior of the roller having an inner tracksurface for the reception of the roller and an exterior-track surfacefor engagement with the surface rolled upon, and a guard memberpivotally supported by the bearing pinand engage able with the trackring to maintain" the roller in constant engagement therewith.

5. A device of the character described comprising a swivelhead,"a pairof bearing arms carried by the head, a bearing pin disposed betWeen thearms, a roller Journaled thereon, a track ring exterior of the rollerhaving an inner track surface for the reception of the roller and anexterior track surface for engagement With the surface rolled upon, anannular rib formed on the inner track surface and centrally thereof, anannular central groove in the roller permitting the roller to straddlethe rib, and a bailshaped guard pivotally mounted on the bearing pin,the upper end of said guard being recessed to straddle the annular trackrib.

6. In a device of the character described a swivel head, a pair ofbearing arms carried thereby, abearing pin supported by the arms, aroller journaled thereon, a track ring surrounding the roller and havinga track surface on its inner side for the reception of the roller, andan exterior track surface for engagement with a surface to be rolledupon, an annular recess formed in each side of the track ring, and acircular plate forming a closure for each side of the track ring, andadapted to be received by said recesses, said plates being eccentricallyjournaled upon the bearing pin.

7. In a device of the character described a swivel head, a pair ofbearing arms carried thereby, a bearing pin supported by the arms, aroller journaled thereon, a track ring surrounding the roller and havinga track surface on its inner side for the reception of the roller, andan exterior track sur face for engagement with a surface to be rolledupon, an annular recess formed in each side of the track ring, acircular plate forming a closure for each side of the track ring andadapted to be received by said recesses, said plates being eccentricallyjournaled upon the bearing pin, and means for maintaining said-platesout of frictional engagement With the roller and the track ring.

ALBION K. NIXON.

